Post by Pooh on Feb 21, 2009 23:01:51 GMT

Variation in Total Solar Irradiance (TSI) is regularly cited as being too low to significantly influence climate change (specifically, global warming). This conclusion had been back-cast using paleo- and dendro-climatology proxies. Based on this claim, most observed warming is attributed to CO2.

I would appreciate some expert comment on “Total Solar Irradiance”.· What wavelengths are included?· How are these measured?· For what period of time have they been measured?· What is the power delivered by these wavelengths?· For what period of time have they been estimated through proxies?· What is the uncertainty of the proxy estimates?· What wavelengths are not included in TSI?· What is the power delivered by the excluded wavelengths?· What wavelengths can be estimated using proxies?An approximate table is found at imagine.gsfc.nasa.gov/docs/science/know_l1/spectrum_chart.html

The SORCE web site defines TSI as: “Solar energy per unit time over a unit area perpendicular to the Sun’s rays at the top of Earth’s atmosphere.” Space Environment Technologies defines it as “the full-disk (whole Sun) solar irradiance at 1 AU (astronomical unit) integrated across all wavelengths.” (http://www.spacewx.com/solar_spectrum.html)

ISO_DIS_21348_E_revB defines solar irradiance as "the Sun’s radiation integrated over the full disk and expressed in SI units of power through a unit of area, W m-2". The full disk includes the corona. "NOTE The commonly used term “full disk” includes all of the Sun’s irradiance coming from the solar photosphere and temperature regimes at higher altitudes, including the chromosphere, transition region, and corona.And: "6.2 Total Solar Irradiance"The Total Solar Irradiance (TSI) is the full-disk (whole Sun) solar irradiance at 1 ua (AU) integrated across all wavelengths and is reported in units of W m-2 (clauses 2.1, 2.2, and 7.2). The solar constant, as described in clause 2.3, is the mean value of the TSI."(ANSI. “Space environment (natural and artificial) — Process for determining solar irradiances.” ISO, December 12, 2005.(Draft) www.spacewx.com/pdf/ISO_DIS_21348_E_revB.pdf)Added 2/23/2009

I had assumed that “Total” meant the entire electromagnetic spectrum, and that any radiation not reflected (albedo) or re-radiated increases the energy of the planet. Upon investigation, however, I found few wavelength references, and those I found did not cover the entire electromagnetic spectrum.

However, if the variation in total solar electromagnetic energy is greater than that claimed for the current TSI, then the warming attributable to CO2 would be less.

Post by Pooh on Feb 21, 2009 23:04:56 GMT

This inquiry about TSI variability does not exclude other candidate drivers of warming temperatures, such as:· A minor effect of CO2,· Clouds and precipitation,· Heat sinks and sources: Oceans and ice sheets, including decadal oscillations· Volcanism,· Solar variability driven by the position of major planets (Vuckovic),· Solar – Earth energy transfer by magnetic fields or particles including electrons,· Solar Wind shielding from Galactic Cosmic Rays and consequent cloud shading,· The position of the Solar System within the Galaxy (Shaviv, Nir. "Cosmic Ray Diffusion from the Galactic Spiral Arms, Iron Meteorites, and a Possible Climatic Connection.” Physical Review Letters, 2007)

Disclosure: I incline towards “All of the above”, to various degrees of timing and influence on the climate of Earth.

Some Forum commentators here have also identified energy, incident upon the earth, which is not included in “TSI”:

jimg points out in Global Warming & Weather Discussion: Global Cooling, reply # Reply #120 on Dec 27, 2008, 4:44pm, …”And TSI doesn't account for high energy radiation interactions. The UV/XUV flux is down about 50% from solar max, and the X-ray is down by a factor of about 10,000.”

Pidgey observed in Tilmari's Global Cooling 2008 Thread Continued, Reply #153 on Sept 27, 2008, 9:26pm“…Now, we certainly have a lot of trouble determining exactly how this plays out since we don't see a remarkable TSI variance and its variation doesn't match the HadCRUT or GLAAM at all. It does kind of follow sunspots.”Perhaps, absorption of the radiant energy is what's affected by the magnetic effects.”

Jarl wrote (In Sunspots not causing global warming or cooling, Reply #27 on Sept 18, 2008, 4:48pm“…UV radiation has 10-100 times more energy than visible light. ”X-rays have 1000-100,000 times more energy than visible light.”If the amount of x-rays and UV have changed, then the total amount of energy hitting the Earth would vary unless the amount of these frequencies are trivial in nature.”

"... proclaim liberty throughout the land to all its inhabitants ..." -- Leviticus 25:10

Post by Pooh on Feb 21, 2009 23:52:05 GMT

“This image, courtesy of Dr. Judith Lean at the US Naval Research Laboratory, shows the spectrum of solar radiation from 10 to 100,000 nm (dark blue), its variability between Solar Maximum and Solar Minimum (green) and the relative transparency of Earth's atmosphere at sea level (light blue). At wavelengths shorter than about 300 nm, there is a relatively large variation in the Sun's extreme UV and x-ray output (greater than 1%), but the Earth's atmosphere is nearly opaque at those wavelengths. “Source:science.nasa.gov/headlines/images/sunbathing/spectrumgif.gif

[/td] [td] What electromagnetic radiation does this show that is excluded from what is being measured as part of TSI? Some appear to have considerable variability compared to visible or IR spectra.· Hard X-Rays· Gamma Rays· Microwaves· Radio wavesHow much energy is delivered to the earth by the radiation that is excluded? [/td]

[td]Does the measured radiation include that of the sun’s corona in addition to that of the solar disk? Yes: See first post of this topic. [/td][/tr][/table]

Post by Pooh on Feb 22, 2009 0:03:25 GMT

This links to a 33-page Zotero report (bibliographic reference data, some abstracts and notes) in pdf format. Not all URLs in the pdf work; those with line breaks in the URL usually do not. If the URL does not display the entire URL when the cursor hovers over it, it will not. But it usually gets to the site where the reference may be found.

Post by socold on Feb 22, 2009 1:11:05 GMT

I am not an expert and this might be slightly wrong, but TSI is supposed to include radiated energy at all spectrums from the sun that reaches earth. Specifically it's the total radiated solar energy reaching Earth's orbit per square meter of a plane facing the Sun.

In practice I don't know how it is measured, other than it's done mainly (if not entirely) by satellites. You might want to check out various TSI reconstructions and then backtrace to their methdology to answer all your questions:www.pmodwrc.ch/pmod.php?topic=tsi/composite/SolarConstant

Post by nautonnier on Feb 22, 2009 1:20:49 GMT

I am not an expert and this might be slightly wrong, but TSI is supposed to include radiated energy at all spectrums from the sun that reaches earth. Specifically it's the total radiated solar energy reaching Earth's orbit per square meter of a plane facing the Sun.

In practice I don't know how it is measured, other than it's done mainly (if not entirely) by satellites. You might want to check out various TSI reconstructions and then backtrace to their methdology to answer all your questions:www.pmodwrc.ch/pmod.php?topic=tsi/composite/SolarConstant

I believe that TSI is not really a good vehicle for assessing the energy transfer from the Sun to the Earth. It should include ALL energy not only radiant energy. For example there is considerable energy in the solar wind, in magnetic effects in 'Flux Transfer Events' and probably others that solar physicists will yet again act surprised about.

Post by poitsplace on Feb 22, 2009 6:50:34 GMT

I believe that TSI is not really a good vehicle for assessing the energy transfer from the Sun to the Earth. It should include ALL energy not only radiant energy. For example there is considerable energy in the solar wind, in magnetic effects in 'Flux Transfer Events' and probably others that solar physicists will yet again act surprised about.

So TSET - Total Solar Energy Transfer . might be a better measure

It's pretty clear what it's talking about though. Generally people don't consider particles in with it. Since it's measured in watts per meter (since someone was asking) it includes the fact that x-rays are far, far more powerful.

Also note the scale is logarithmic on that TSI variability chart. It makes things doubly confusing. AGW proponents latch on to the fact that SURELY the UV can't have much of an affect because much of the higher UV is relatively weak. BUT...if you'll notice the variability ramps up at the same rate (and still logarithmically as it slacks back off) and so it COMPLETELY offsets the other curve.

Suffice it to say that the increases in UV are substantial (greater than 1%) and account for far more than would be expected from a simple .1% variability of the TSI. Since this increase comes at the expense of other wavelengths and because about 1/2 of the rest of the spectrum is reflected outright (ballpark) quite a lot of that increase in UV is converted directly into heat in the atmosphere.

I have no clue what the total energy increase is, it's beyond my ability to calculate anyway...and the data is sketchy because quite frankly...nobody seems to care..and we haven't had a lot of time to collect data. In the current climate solar forcing is shrugged off as so insignificant that they usually don't even include it in rough calculations.

Final side note...the .1% variability is not exactly correct. Since the minimum we've found that the sun can vary by a little bit more than that. Currently I believe it's at .13% variation and possibly still falling.

Socold: Thank you! We agree on what TSI is supposed to be (Start of Thread, SORCE and Space Environment Technologies).

One of the facts I would like to find is "What wavelengths are included" in the measurement of TSI; do the measurements cover all of what TSI is supposed to be? E.g., has all of the TSI been measured before TSI was said to have low variability? Further, is the power delivered by the missing spectra significant?

You have confirmed that backtracing the methodology may be the only resort; that what I was trying to do and hoped to avoid by finding a reference that showed it. I slogged though a little under 40 references so far, and have not found a consolidated record of wavelengths measured.

Your pmodwrc reference will help. It identifies PMOD, ACRIM, ACRIM I, ACRIM II, IRMB and ERBE as follow-ups. HF and DIARAD are indicated as radiometers; HF is also an abbreviation for HF wavelengths.

(One of reasons for posting this question here is that some other references are sequestered in "pay-to-play" academic journal archives.)

"... proclaim liberty throughout the land to all its inhabitants ..." -- Leviticus 25:10

Post by Pooh on Feb 22, 2009 7:40:13 GMT

I believe that TSI is not really a good vehicle for assessing the energy transfer from the Sun to the Earth. It should include ALL energy not only radiant energy. For example there is considerable energy in the solar wind, in magnetic effects in 'Flux Transfer Events' and probably others that solar physicists will yet again act surprised about.

So TSET - Total Solar Energy Transfer . might be a better measure

nautonnier and poitsplace:

I agree, but I don't know where to find these measures, their level and their variability over decades. We have only around 40 years of satellite data, and close to zip before that on some of the more recently identified influences. See the list of "other candidate drivers" in Reply #1.

I guess I bugged out, and took TSI wavelengths as the issue most likely to have published facts, and the factor most closely "advertised" in labeling CO2 as the culprit.

Nonetheless, I think documenting the measured TSI, its variability and its omissions is a worthwhile first step.

"... proclaim liberty throughout the land to all its inhabitants ..." -- Leviticus 25:10

Post by Pooh on Feb 22, 2009 7:56:42 GMT

... Generally people don't consider particles in with it. Since it's measured in watts per meter (since someone was asking) it includes the fact that x-rays are far, far more powerful.... BUT...if you'll notice the variability ramps up at the same rate (and still logarithmically as it slacks back off) and so it COMPLETELY offsets the other curve. Suffice it to say that the increases in UV are substantial (greater than 1%) and account for far more than would be expected from a simple .1% variability of the TSI. ... a lot of that increase in UV is converted directly into heat in the atmosphere.

Your post is a super illustration of why I started this thread.

We know that other wavelength clusters of energy and variability are out there.

What I don't yet know is whether they were included in the TSI and variability as used by the IPCC.

I suspect not. Much of this is recent science, and unlikely to have proxies dating back centuries. Also, TSI records apparently started using only visible light and near IR; continuity of definition is an argument. However, that argument would invalidate using TSI as the measure of total solar energy.

"... proclaim liberty throughout the land to all its inhabitants ..." -- Leviticus 25:10

Post by poitsplace on Feb 22, 2009 10:43:32 GMT

What I don't yet know is whether they were included in the TSI and variability as used by the IPCC.

I suspect not. Much of this is recent science, and unlikely to have proxies dating back centuries. Also, TSI records apparently started using only visible light and near IR; continuity of definition is an argument. However, that argument would invalidate using TSI as the measure of total solar energy.

Also most definitely not included in the models (nor observed in the models) is the earth's outer atmosphere dropping by 100 miles in the absence of high solar activity. That's got to take a pretty substantial amount of energy...and although the air is tenuous at those altitudes, the concentration of oxygen is 500x higher than CO2. The loss of up to 2.7% of earth's capture cross section has to have a LOT more impact than the piddly CO2 increases.

I never could find any references to the overall power of the solar wind though. I guess you could use the historical data on density and velocity and make a couple rough estimates based on the capture cross section of the earth including its magnetic field.

Post by nautonnier on Feb 22, 2009 13:32:45 GMT

... Generally people don't consider particles in with it. Since it's measured in watts per meter (since someone was asking) it includes the fact that x-rays are far, far more powerful.... BUT...if you'll notice the variability ramps up at the same rate (and still logarithmically as it slacks back off) and so it COMPLETELY offsets the other curve. Suffice it to say that the increases in UV are substantial (greater than 1%) and account for far more than would be expected from a simple .1% variability of the TSI. ... a lot of that increase in UV is converted directly into heat in the atmosphere.

Your post is a super illustration of why I started this thread.

We know that other wavelength clusters of energy and variability are out there.

What I don't yet know is whether they were included in the TSI and variability as used by the IPCC.

I suspect not. Much of this is recent science, and unlikely to have proxies dating back centuries. Also, TSI records apparently started using only visible light and near IR; continuity of definition is an argument. However, that argument would invalidate using TSI as the measure of total solar energy.

"What I don't yet know is whether they were included in the TSI and variability as used by the IPCC.

I suspect not. Much of this is recent science, and unlikely to have proxies dating back centuries."

I also suspect not - but for a different reason - they have no wish to expose all their previous 'we cannot think of anything else so it must be CO2' position. They cannot even admit that their models in AR4 are wrong.

Can you imagine how much moral strength it would take to say - "The warming is not green house gases - it has been found that it is due to unexpected and previously unmeasured changes in the Sun's output."? They are riding a tiger and cannot dismount.

This is the real reason behind the 'its settled science' claims. They really cannot mentally take the stress of even taking the risk of looking for any different cause for warming/cooling of the climate. I believe this may also be the reason for some of the outright hostility to people investigating or espousing different causes for climate variability.